This application claims the priority of German application 101 17 010.6, filed Apr. 5, 2001, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a bodywork frame for a motor vehicle.
Such a bodywork frame normally has two lateral load bearing columns which, in the case of a passenger car, are designated xe2x80x9cAxe2x80x9d, xe2x80x9cBxe2x80x9d or xe2x80x9cCxe2x80x9d columns in accordance with their positions. DE 40 16 730 C2 discloses load bearing columns for a bodywork frame of this type which have column-like hollow bodies. Each hollow body has two profiled shells which enclose a cavity in which a tubular element is arranged, which extends in the longitudinal direction of the hollow body and is fixed to the hollow body.
In a bodywork frame whose load bearing columns are arranged in the region of the backrest of a driver or passenger seat (xe2x80x9cB columnsxe2x80x9d), for modern motor vehicles, a particularly high side impact stability is required in order, in the event of a side impact, to be able to ensure the undisrupted unfolding of a side impact air bag unfolding between the back rest and load bearing column. In addition, the passenger compartment should ensure the safety of the vehicle occupants, even when the vehicle is turned over. Furthermore, there is the desire to incline the load bearing columns of the load bearing frame to the greatest extent possible with respect to a vertical axis, in order, as a result, to be able to design the vehicle to be flatter.
The present invention tackles the problem of specifying, for a bodywork frame of the type mentioned at the beginning, a design form which ensures increased side impact protection.
According to the invention, this problem is solved by a bodywork frame for a motor vehicle, in particular a passenger car, comprising two lateral load bearing columns, which are supported on each other, at a roof side, via a pressure-stable roof cross member and, at a floor side, on a longitudinal tunnel, in each case via a pressure-stable seat cross member. The invention also concerns a process of providing such a bodywork frame.
The invention is based on the general idea of configuring the bodywork frame in such a way that an annularly closed assembly is formed by the load bearing columns. As a result, intensive support for the load bearing columns is ensured in the transverse direction of the vehicle. In the bodywork frame according to the invention, this is implemented by supporting the two load bearing columns on each other at the roof side via a pressure-stable roof cross member and at the floor side via an assembly of seat cross members and longitudinal tunnel. In the region of the load bearing columns, the bodywork frame thus has a high dimensional stability, in particular in the event of a side impact and in the event of turning over. Therefore, the bodywork frame according to the invention, if one of its load bearing columns is used as a B column, can ensure a sufficient spacing between the B column and back rest for a sufficiently long time in order to ensure the unfolding of a side impact air bag. As a result of the increased stability of the B column, the load on the A column can be relieved, so that the latter can be designed flatter, narrower and with an increased inclination.
In a preferred embodiment, the two seat cross members can additionally be supported on each other by a pressure-stable bridge beam which bridges over the longitudinal tunnel. By means of this, the transverse support of the two load bearing columns on each other in the floor area is improved considerably.
Roof cross members and/or seat cross members and/or bridge beams are preferably equipped with a pressure-stable hollow profile. Using hollow profiles, a particularly high pressure stability can be achieved, it being possible at the same time to implement a low component weight.
In a particularly advantageous embodiment, each of the load bearing columns can be equipped with a column-like hollow body, in which a tubular element extends substantially in the longitudinal direction of the hollow body. A tubular element has very high stiffness values, so that the stability of the load bearing columns and therefore of the bodywork frame is improved.
Further important features and advantages of the invention will be apparent from dependent claims, the drawings, and the associated description of the drawings.
The features mentioned above and the features still to be explained below can be used not only in the respectively specified combination but also in other combinations or on their own without departing from the scope of the present invention.